title: Small head circumference at birth and early age at adiposity rebound.
abstract: OBJECTIVE
  The adiposity rebound is the age in childhood when body mass index is at a minimum before increasing again. The age at rebound is highly variable. An early age is associated with increased obesity in later childhood and adult life. We have reported that an early rebound is predicted by low weight gain between birth and 1 year of age and resulting low body mass index at 1 year. Here, we examine whether age at adiposity rebound is determined by influences during infancy or is a consequence of foetal growth. Our hypothesis was that measurements of body size at birth are related to age at adiposity rebound.
  
  
  METHODS
  Longitudinal study of 2877 children born in Helsinki, Finland, during 1934-1944.
  
  
  RESULTS
  Early age at adiposity rebound was associated with small head circumference and biparietal diameter at birth, but not with other measurements of body size at birth. The mean age at adiposity rebound rose from 5.8 years in babies with a head circumference of ≤33 cm to 6.2 in babies with a head circumference of >36 cm (P for trend = 0.007). The association between thinness in infancy and early rebound became apparent at 6 months of age. It was not associated with adverse living conditions. In a simultaneous regression, small head circumference at birth, high mother's body mass index and tall maternal stature each had statistically significant trends with early adiposity rebound (P = 0.002, <0.001, 0.004).
  
  
  CONCLUSIONS
  We hypothesize that the small head size at birth that preceded an early adiposity rebound was the result of inability to sustain a rapid intra-uterine growth trajectory initiated in association with large maternal body size. This was followed by catch-up growth in infancy, and we hypothesize that this depleted the infant's fat stores.
authors.affiliation: Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland; Department of General Practice and Primary Health Care, University of Helsinki, Helsinki, Finland; Vasa Central Hospital, Vasa, Finland; Folkhälsan Research Centre, Helsingfors Universitet, Helsinki, Finland; Unit of General Practice, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: J G
authors.initials: JG
authors.lastname: Eriksson
authors.forename: E
authors.initials: E
authors.lastname: Kajantie
authors.forename: M
authors.initials: M
authors.lastname: Lampl
authors.forename: C
authors.initials: C
authors.lastname: Osmond
authors.forename: D J P
authors.initials: DJ
authors.lastname: Barker
mesh_terms: D050154:Adiposity / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology*; D049628:Body Size / Q000502:physiology*; D002675:Child, Preschool; D005260:Female; D006257:Head / Q000033:anatomy & histology* / Q000254:growth & development*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D015430:Weight Gain / Q000502:physiology*; D055815:Young Adult
keywords: adiposity rebound; foetal growth; infant growth